This Should Work (10)

You will earn the bolt gun as you progress through the fourteenth mission, "The Descent."

To use the bolt gun, hold LT , then hold down RT . Wait for the gun to charge up, then release RT after a few seconds.

Alternatively, you can get this achievement in Survivor mode as soon as you start Alien: Isolation if you have the Crew Expendable DLC. With Crew Expendable you can use Dallas, Ellen Ripley, and Parker in Survivor mode.

Both Dallas and Parker automatically have the bolt gun in their inventory.